Emotional response can be triggered be caused by a specific event and that the person experiencing it is aware of the cause, such as a child?s excitement at the sound of an ice cream truck.

However, this is not always easy to replicate in virtual environments, even with suspension of disbelief ? without evoking the human element triggered by real, long-term interactions with other people within them.

In the time span before that long-term bonding can occur, or in situations in VR without many or indeed any other sentient minds present, triggering emotional response and thus deeper bonding is difficult at best.

Now, new research by psychologists Kirsten Ruys and Diedrick Stapel of the Tilburg Institute for Behavioural Economics Research at Tillburg University in The Netherlands suggests emotions also can be unconsciously evoked and manipulated.

They have uncovered the first empirical evidence to suggest humans do not need to be aware of the event that caused their mood or feelings in order to be affected by it.

The scientists hypothesised that, since humans have evolved to respond quickly and unconsciously to stimuli, they should be able to react to an emotional event without full awareness: ?You are likely to live longer if you immediately stop moving at the sight of a growling grizzly bear and do not need full awareness for such a response to be instigated,? explained Ruys and Stapel.

Participants in their study were separated into three groups and were told that very short flashes would appear on a computer screen. They were then instructed to press the ?R? key if it appeared on the right side of the screen or the ?L? key if it appeared on the left.

In actuality, the ?flashes? were subliminal images selected to elicit fear, disgust or no emotion at all. The images flashed at varying speeds making it impossible for the participants to be fully conscious of their presence. In other words, the participants were unaware that they were viewing images of growling dogs and dirty toilets or even neutral images, such as horses or chairs.

The participants then underwent three tests to measure the effect of the images on their cognition, feelings and behaviour. For the cognitive measure, they completed word fragments with a variety of words including those that expressed disgust, fear, anger, generally negative, generally positive and neutral feelings. Next, participants rated the overall positivity or negativity of their mood and the extent to which they felt fearful, disgusted, satisfied, relieved, proud, angry, shameful and joyful on 7-point scales.

The intriguing results, which appear in the April issue of Psychological Science, a journal of the Association for Psychological Science, strongly support the psychologists? theory.

The psychologists also found that after quick (120ms) speed exposures to emotional stimuli, a general, negative mood developed accompanied by a specific emotion, such as fear after seeing fearful pictures. After the super-quick (40ms) speed exposure, only a general negative mood was induced without a specific emotion involved. These empirical findings are the first to demonstrate that specific emotions can be evoked without awareness of the cause and that a person?s global mood can develop into a specific emotion.

Whilst not advocating the use of subliminal flashing in virtual environments, this research forms empirical evidence that the type of stimulus the virtual environment delivers, can actually affect participant?s mood. Even the briefest exposures to tiny details all help form an emotional response.